“All theory is grey, but the precious tree of life is green.” Maurice Ravel to Hélène Jourdan-Morhange, describing Schoenberg’s intellectualism.  Hélène Jourdan-Morhange, Ravel et nous (Geneva, 1945), p. 104.  Cited in:  Nichols, Roger (1987) Ravel Remembered.  London: Faber & Faber., p. 61.